The invention relates to the field calibration of gas detectors, in which the concentration of a reference gas is determined.
It is known for test devices to be recalibrated at regular intervals. This may be done by measuring the concentration of a reference gas. The reference gas concentration may be a known quantity of reference gas. Recalibration is done in the factory or in a special test laboratory. This procedure is complex and entails high costs, and is impractical for the test devices widely used in the field.